Every stanza of this poem is an apology, and the speaker seems to be saying sorry to someone whose approval they badly want, perhaps a parent or other adult, though the poem never says. The apologies start with abandonment and feeling "not worth it," then move to comparison with someone else ("what he did"), and then to small failures like unfinished homework and a bad quiz. By the fourth stanza the tone turns darker. The speaker admits to hiding their pain and cutting themselves, and even that is framed as something to apologize for.
What stands out is how the speaker blames themselves for everything, from schoolwork to "mess[ing] up lives." Pain is treated as a failure, not as something that needs care. The repetition of "i'm sorry" and the lowercase, plain style make the poem feel quiet, tired, and heavy. The single "i'm sorry" at the end, with nothing after it, leaves a mood of hopelessness and isolation.